nephron (n.)

before vowels nephr-, word-forming element meaning "kidney, kidneys," from Greek nephros "a kidney" (plural nephroi), from PIE *negwhro- "kidney" (source also of Latin nefrones, Old Norse nyra, Dutch nier, German Niere "kidney").

"adrenaline," 1883, from epi- "upon" + Greek nephros "kidney" (see nephron) + chemical suffix -ine (2). So called because the adrenal glands are on the kidneys.